Sub-pixel edge location algorithm for bilevel images

Donghong Hu, Michitaka Kameyama, Xinmeng Chen, Ling Zhang, Lang Li

Research output: Contribution to journalArticlepeer-review


Accurate edge localization of bilevel images is of primary importance in barcode decoding. In the sub-pixel edge location algorithm for bilevel images, the bilevel image (barcode) imaging process is modeled as a square wave convoluted with a Gaussian kernel and then sampled discretely by pixel arrays. Based on the gray levels of the pixels, assumed sub-pixel edge locations are set and adjusted so that the discrepancy of the theoretical gray level of pixels and the actual gray level of pixels reaches the minimum and then the best approximation of the actual sub-pixel edges of the bilevel image is obtained. Examples are presented to illustrate the techniques of the algorithm which can solve the problems of edge location or signal recovery of bilevel images in the case of the two features: one is that the support of the Gaussian kernel is comparable to the distance of the adjacent edges; the other is that the distance between the adjacent edges is comparable to the distance of the adjacent pixels.

Original languageEnglish
Pages (from-to)422-426
Number of pages5
JournalWuhan University Journal of Natural Sciences
Issue number5
Publication statusPublished - 2010


  • digital image processing
  • image boundary analysis
  • image edge analysis
  • image restoration
  • point spread functions

ASJC Scopus subject areas

  • General


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